Bataka Evmorfia P, Maletsika Persefoni, Nakas Christos T
Laboratory of Biometry, Department of Agriculture, Crop Production and Rural Environment, University of Thessaly, 384 46 Volos, Greece.
Laboratory of Pomology, Department of Agriculture, Crop Production and Rural Environment, University of Thessaly, 384 46 Volos, Greece.
Sensors (Basel). 2024 Jan 12;24(2):490. doi: 10.3390/s24020490.
Open-source devices are nowadays used in a vast number of research fields like medicine, education, agriculture, and sports, among others. In this work, an open-source, portable, low-cost pH logger, appropriate for in situ measurements, was designed and developed to assist in experiments on agricultural produce manufacturing. Τhe device was calibrated manually using pH buffers for values of 4.01 and 7.01. Then, it was tested by manually measuring the pH from the juice of citrus fruits. A waterproof temperature sensor was added to the device for temperature compensation when measuring the pH. A formal method comparison process between the open-source device and a Hanna HI9024 Waterproof pH Meter was designed to assess their agreement. We derived indices of agreement and graphical assessment tools using mixed-effects models. The advantages and disadvantages of interpreting agreement through the proposed procedure are discussed. In our illustration, the indices reported mediocre agreement and the subsequent similarity analysis revealed a fixed bias of 0.22 pH units. After recalibration, agreement between the devices improved to excellent levels. The process can be followed in general to avoid misleading or over-simplistic results of studies reporting solely correlation coefficients for formal comparison purposes.
如今，开源设备被广泛应用于众多研究领域，如医学、教育、农业和体育等。在这项工作中，设计并开发了一种适用于原位测量的开源、便携式、低成本pH记录仪，以辅助农产品制造实验。该设备使用pH值为4.01和7.01的pH缓冲液进行手动校准。然后，通过手动测量柑橘类水果汁液的pH值对其进行测试。在测量pH值时，为该设备添加了一个防水温度传感器用于温度补偿。设计了一个开源设备与Hanna HI9024防水pH计之间的正式方法比较过程，以评估它们的一致性。我们使用混合效应模型得出了一致性指标和图形评估工具。讨论了通过所提出的程序解释一致性的优缺点。在我们的示例中，指标显示一致性一般，随后的相似性分析揭示了0.22个pH单位的固定偏差。重新校准后，设备之间的一致性提高到了优秀水平。一般可以遵循这个过程，以避免仅为正式比较目的而报告相关系数的研究产生误导性或过于简单的结果。
